Thursday, June 20, 2019

Finish Kit (....and others for Final Assembly)

Roll Trim Calibrated, Leak Test Static System ( 4 hrs )

Calibrated Aileron or Roll Trim in G3X.  Discovered I had to reverse Roll Trim Switch direction in Config under Trim. Confirmed in Systems Config.  Garmin Prod Support helped me check direction with and without GSA 28 AP servos "on" by simply pulling AP Servos CB.  Checked OK.    Added neutral or center tick mark to display of position by setting a green "zone" at +2, -2.  Finding Neutral is difficult due to the springs and slight hysteresis of the Aileron system, so I did best I could to determine "center" position (alignment with Wing Tips on each side, or Flaps).  Contacted Tim Mckune at Byerly Aviation Avionics to arrange Pitot/Static test and Transponder test.  They're swamped with ADS-B installations due to 2020 deadline.  So they're requesting I first leak test to avoid issues when they do their tests.   On May 20, Garmin Prod Support recommended I don't do leak tests w/o special equipment due to hyper sensitive sensors in GSU 25, and G5.  They were confident I wouldn't have leaks in either my quick connections or tapered threaded fittings on back of units.    So...to compromise, I'm testing with the lines disconnected from GSU 25 and G5...so no possibility of damaging sensors (won't reveal if fittings on units are leaking, but if during special tests we determine they are...they can be accessed quickly to remove and re-insert with fresh Permatex #3.   Before deciding not to leak test in May, I'd purchased syringes and other items to create a manometer.   Pics below show a simple set-up.  I don't need the scale for a leak rate test, but it does provide easy tracking of change.   I'm using hemostats (not pictured) to clamp tubing to check for leaks in test equipment, and isolate syringe (which may leak).  So far, all those connections are leak free.  BUT, I've determined the Static system is leaking significantly.  I'm going to have to crawl into Aft Fuselage to check connections, since otherwise it's only one piece of tubing from Aft Fuse to my connection for leak rate test.
Top of IP with Canopy open.  GSU 25 on left has AOA blue
line, while Static line (red) and Pitot (white) are T'd to both
G5 and GSU 25.  I'm disconnecting at tube connection 
to T, so I avoid any risk to sensors.

Jury rigged leak rate test equipment.  In-line small engine gas filter
 limits contaminants to Static system, while also acting as orifice
(not critical w/o sensors involved).